Hybrid phone and method of acquiring channel in the hybrid phone

ABSTRACT

A hybrid phone to acquire channels has a first communication mode supporting voice/low-rate data communications and a second communication mode supporting high-rate data communication, and includes a phone control unit having a communication processor controlling voice/data communications according to programs stored in a memory. The communication processor includes a channel acquisition processor attempting to acquire channels for the first and second communication modes. If the channel acquisition processor cannot acquire a channel for the second communication mode within a predetermined time, the channel acquisition processor stops attempting to acquire the channel for the second communication mode and reattempts to acquire the channel for the first communication mode. If the channel acquisition processor acquires the channel for the first communication mode, the channel acquisition processor reattempts to acquire the channel for the second communication mode.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/263,241, filed on Oct. 31, 2005 and claims the benefit of and thepriority from Korean Patent Application No. 10-2005-0000550, filed onJan. 4, 2005, which are both hereby incorporated by reference for allpurpose as if fully set forth herein.

BACKGROUND

1. Field of the Invention

The present invention relates to a mobile communication terminal and,more particularly, to a technology of improving voice call success ratioin a hybrid phone supporting voice, low-rate and high-rate datacommunications.

2. Description of Related Art

A hybrid phone refers to a mobile communication terminal which allows auser to use voice and low-rate data communication services over anIS-95/1x network and to use a high-rate data communication service overa High Data Rate (HDR) network by combining IS-95/1x technology with HDRtechnology.

The HDR technology refers to a packet wireless data transmissiontechnology developed using CDMA technology by Qualcomm Inc., whichallows mega class high-speed data transmission, e.g., a maximumtransmission speed of 2.547 Mbps within a CDMA cell site. HDR offers atransmission speed as fast as 16 times the maximum transmission speed of153.6 Kbps on a forward channel of the IS-95/1x system and also providesa data transmission capacity as much as 5 times that of the IS-95/1xsystem.

HDR offers a user with a hybrid phone voice and high-speed wireless dataservices by means of an HDR access point function provided independentlyfrom a Base Transceiver Station (BTS) or an HDR access point functionincorporated in the BTS.

FIG. 1 is a block diagram of a mobile communication system according tothe prior art. A mobile communication system 100 includes an IS-95/1xnetwork module 110 processing voice communication and an HDR networkmodule 120 processing high-speed data communication. The IS-95/1xnetwork module 110 includes an IS-95/1x BTS 111, a Base StationController (BSC) 112, a Mobile Switching Center (MSC) 113, and anInterWorking Function (IWF) 116. The HDR network module 120 includes anHDR access point 121, a BSC 112, a Packet Control Function (PCF) 123, aPacket Data Serving Node (PDSN) 124, and a Home Agent (HA) 125.

The IS-95/1x BTS 111 establishes a wireless connection with a hybridphone 200 in an IS-95/1x mode, and acts to convert signal formats to besuitable for wireless and wireline links. The BSC 112 handles allocationof radio channels, receives measurements from the hybrid phone, andcontrols handovers from BTS to BTS. The MSC 113 is a sophisticatedtelephone exchange which provides circuit-switched calling and mobilitymanagement to the hybrid phone roaming within the area that it serves.The IWF 116 is used to provide circuit switched data services whenconnecting a mobile communication network to the Internet.

The HDR access point 121 establishes a wireless connection with thehybrid phone 200 for high-speed data communication and controls datatransfer with the hybrid phone 200. The HDR access point 121 may beprovided separately from or incorporated in the IS-95/1x BTS 111 of theIS-95/1x network module 110. The BSC 112, which is also used for theIS-95/1x network module 110, performs a process required for operationof the HDR access point 121. The PCF 123 controls the transmission ofpackets between the HDR access point 121 and the PDSN 124. The PDSN 124is responsible for the establishment, maintenance and termination of aPPP (Point-to-Point Protocol) session towards hybrid phones. The HA 125performs mobile IP authentication for packet data services in connectionwith the PDSN 124.

The hybrid phone 200 detects signal strengths of base stations over apilot channel upon initial power-on, makes synchronization with a basestation having the largest signal strength over a sync channel, andrequests hybrid phone location registration and subscriberauthentication from the IS-95/1x BTS 111. The hybrid phone 200 performsa channel acquisition process upon completion of successful locationregistration and subscriber authentication.

The hybrid phone 200 acquires a channel for voice and low-rate datacommunication modes using the IS-95/1x technology and acquires a channelfor a high-rate data communication mode by making reference to aPreferred Roaming List (PRL) file containing a channel list of eachcommunication mode stored in a memory upon manufacture of the hybridphone 200.

FIG. 2 is a flow chart of a conventional channel acquisition process ina hybrid phone. Upon power-on, a hybrid phone attempts to acquire achannel for a first communication mode supporting voice and low-ratedata communications (operations S401, S402). The hybrid phone switchesthe first communication mode to an idle state after acquiring thechannel (operations S403, S404). Subsequently, the hybrid phone attemptsto acquire a channel for a second communication mode supportinghigh-rate date communication (operation S405). The hybrid phonedetermines whether or not the channel for the second communication modehas been acquired (operation S406). If the channel is determined to havebeen acquired, the second communication mode is switched to an idlestate (operation S407). The hybrid phone reattempts to acquire a channelfor the first communication mode. If the channel is determined to havebeen acquired, operations S402 to S406 are repeated to attempt toacquire a channel for the second communication mode. Next, the hybridphone determines whether or not a power-off signal is input (operationS408). If the power-off signal is not input, operation S402 is performedto attempt to acquire a channel for the first communication mode. If thepower-off signal is input, the channel acquisition process is ended.

As described above, the hybrid phone is configured to acquire channelsfor each communication mode so that a user can use both voice/low-ratedata communication services and a high-rate data communication service.That is, the hybrid phone acquires a channel for the first communicationmode for voice and low-rate data communications and a channel for thesecond communication mode for high-rate data communication, andperiodically monitors slots assigned for the first and secondcommunication modes to perform a paging process.

However, when the hybrid phone is located in an area in which datacommunication services do not work well, e.g., in an area in whichchannels for voice and low-rate data communication modes can be acquiredbut channels for a high-rate data communication mode cannot be acquired,the hybrid phone continuously attempts to acquire channels for thehigh-rate data communication mode while the voice and low-rate datacommunication mode is maintained in an idle state. In this case, it isdifficult for the hybrid phone to receive voice calls normally.Accordingly, there is a problem in that the hybrid phone has a lowervoice call success ratio than a mobile phone supporting only voice andlow-rate data communication services.

SUMMARY

Exemplary embodiments of the present invention provide a hybrid phonesupporting a voice/low-rate data communication service and a high-ratedata communication service, which may be capable of providing voice callsuccess ratio as high as a mobile phone supporting only voice andlow-rate data communication services.

Additional features of the invention will be set forth in thedescription which follows, and in part will be apparent from thedescription, or may be learned by practice of the invention.

An exemplary embodiment of the present invention discloses a hybridphone having a first communication mode supporting voice and low-ratedata communications and a second communication mode supporting high-ratedata communication, the hybrid phone including: a key input unit; adisplay unit displaying menus and operation states; a wirelesscommunication unit extracting voice and data signals from a wirelesssignal transmitted and received via an antenna; a voice processorinputting and outputting the voice signal from the wirelesscommunication unit through a microphone and a speaker; a memory storingexecution programs and related data; and a phone control unit having acommunication processor which controls voice and data communicationsaccording to the execution program stored in the memory, where thecommunication processor further includes a channel acquisition processorwhich attempts to acquire channels for the first and secondcommunication modes, and if the channel acquisition processor does notacquire a channel for the second communication mode within apredetermined time interval, the channel acquisition processor stopsattempting to acquire a channel for the second communication mode andreattempts to acquire a channel for the first communication mode, and,if the channel acquisition processor acquires a channel for the firstcommunication mode, the channel acquisition processor reattempts toacquire a channel for the second communication mode.

The channel acquisition processor may attempt to acquire a channelaccording to a channel list of each communication mode contained in aPRL (Preferred Roaming List) file stored in the memory.

An exemplary embodiment of the present invention also discloses a methodof acquiring a channel in a hybrid phone having a first communicationmode supporting voice and low-rate data communications and a secondcommunication mode supporting high-rate data communication, the methodincluding the operations of: attempting to acquire a channel for thefirst communication mode; switching the first communication mode to anidle state after the channel is acquired; attempting to acquire achannel for the second communication mode; switching the secondcommunication mode to an idle state after the channel is acquired, and,if the channel has not been acquired, determining whether or not thetime set for the channel acquisition has been elapsed; and reattemptingto acquire a channel for the second communication mode if the time setfor the channel acquisition is not determined to have been elapsed, andstopping attempting to acquire a channel for the second communicationmode if the time set for the channel acquisition is determined to havebeen elapsed.

The operation of attempting to acquire a channel may include attemptingto acquire a channel according to a channel list of each communicationmode contained in a PRL file stored in a memory of the hybrid phone.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present inventionwill become more apparent by describing in detail exemplary embodimentsthereof with reference to the attached drawings in which:

FIG. 1 is a block diagram of a mobile communication network of the priorart;

FIG. 2 is a flow chart of a conventional channel acquisition process ofa hybrid phone;

FIG. 3 is a block diagram of a hybrid phone in accordance with anembodiment of the present invention; and

FIG. 4 is a flow chart of a channel acquisition process of a channelacquisition processor of FIG. 3.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Exemplary embodiments in accordance with the present invention will nowbe described in more detail with reference to the accompanying drawings.

FIG. 3 is a block diagram of a hybrid phone in accordance with anembodiment of the present invention.

The hybrid phone includes a key input unit 210, a display unit 220, awireless communication unit 230, a voice processor 240, a memory 250,and a phone control unit 260.

The key input unit 210 is a typical keypad controlled by a user to senda signal to the phone control unit 260. The display unit 220 acts todisplay menus and operation states of the hybrid phone for the user. Anexample of the display unit 220 is a liquid crystal display (LCD)device. The wireless communication unit 230 includes an antenna and aradio frequency (RF) module to communicate with base stations. Thewireless communication unit 230 is construed to be applicable toexisting mobile communication systems, such as CDMA, GSM, and W-CDMA,and future mobile communication systems. The voice processor 240converts digital voice data into an analog voice signal and vice versa.The voice processor 240 includes an audio amplifier, a filter, and thelike.

The memory 250 may be a signal chip configured to include a StaticRandom Access Memory (SRAM) having a capacity of several megabits and aflash memory having a capacity of tens of megabits. In one embodiment,the memory 250 stores a Preferred Roaming List (PRL) file. The PRL fileincludes an acquisition table (ACQ table) and a system table. Theacquisition table includes a plurality of indexes each indicating apriority of channel acquisition in each communication mode in each area.The system table includes area information, PRL information, acquisitiontable index, roaming index, system ID (SID), and network ID (NID). ThePRL file may be stored in the memory upon manufacture of a hybrid phone,or may be provided to a hybrid phone when the hybrid phone requests adownload or upgrade from an Over-The-Air (OTA) server which is providedand operated in a mobile communication network.

A baseband circuit of the wireless communication unit 230 and mostcircuits of the phone control unit 260 are integrated into acommercially available single integrated circuit. The integrated circuitincludes hardware dedicated for communication, a digital signalprocessor, and a general-purpose microprocessor. The phone control unit260 includes a communication processor 261 for controlling voice datacommunication.

The communication processor 261 includes a first communication mode forsupporting voice and low-rate data communications, and a secondcommunication mode for supporting high-rate data communication. Thecommunication processor 261 further includes a channel acquisitionprocessor 2611 which attempts to acquire channels for the first andsecond communication modes. If the channel acquisition processor 2611does not acquire a channel for the second communication mode within apredetermined time interval, the channel acquisition processor 2611stops attempting to acquire a channel for the second communication modeand reattempts to acquire a channel for the first communication mode. Ifthe channel acquisition processor 2611 acquires a channel for the firstcommunication mode, the channel acquisition processor 2611 reattempts toacquire a channel for the second communication mode.

FIG. 4 is a flow chart of a channel acquisition process in the channelacquisition processor 2611 shown in FIG. 3. As described above, a hybridphone according to an exemplary embodiment of the present inventionincludes a first communication mode for supporting voice and low-ratedata communication services, and a second communication mode forsupporting a high-rate data communication service.

The channel acquisition unit 2611 attempts to acquire a channel for thefirst communication mode upon power-on of the hybrid phone (operationsS801 and S802). The channel acquisition processor 2611 changes the firstcommunication mode to an idle state after the channel is acquired(operations S803 and S804). Next, the channel acquisition processor 2611attempts to acquire a channel for the second communication mode(operation S805). According to an embodiment of the present invention,the channel acquisition processor 2611 attempts to acquire channelsaccording to a channel list of each communication mode contained in PRLinformation stored in a memory upon attempting to acquire channels forthe first and second communication modes.

The channel acquisition processor 2611 determines whether or not achannel for the second communication mode has been acquired (operationS806). If the channel for the second communication mode is notdetermined to have been acquired, the channel acquisition processor 2611determines whether or not the time set for the channel acquisition hasbeen elapsed (operation S807).

If the time set for the channel acquisition is not determined to havebeen elapsed, the channel acquisition processor 2611 reattempts toacquire a channel for the second communication mode. If the set time haselapsed, the channel acquisition processor 2611 stops attempting toacquire a channel for the second communication mode (operation S808).Next, the channel acquisition processor 2611 determines whether or not apower-off signal is input. If the power-off signal is not input, thechannel acquisition processor 2611 attempts to acquire a channel for thefirst communication mode (operation S809).

Meanwhile, if the channel for the second communication mode isdetermined to have been acquired in operation S806, the secondcommunication mode is changed to an idle state (operation S810).

As apparent from the above description, according to the embodiments ofthe present invention, a hybrid phone supporting a voice/low-rate datacommunication service and a high-rate data communication service may becapable of providing voice call success ratio as high as a mobile phonesupporting only voice and low-rate data communication services.

While the present invention has been described with reference toexemplary embodiments thereof, it will be understood by those skilled inthe art that various changes in form and details may be made thereinwithout departing from the scope of the present invention as defined bythe following claims and their equivalents.

1. A mobile terminal to support at least two communication modes, themobile terminal comprising: a wireless communication unit to communicatesignals via an antenna; a memory to store an execution program and data;and a channel acquisition processor to acquire at least one channel fora first communication mode and a second communication mode within apredetermined time interval according to the execution program in thememory, wherein if the predetermined time interval elapses, the channelacquisition processor stops acquiring the channel for the secondcommunication mode.
 2. The mobile terminal of claim 1, wherein thechannel acquisition processor attempts to acquire at least one of thechannel for the first communication mode and the channel for the secondcommunication mode according to a channel list of each communicationmode contained in a Preferred Roaming List(PRL) file stored in thememory.
 3. The mobile terminal of claim 1, wherein the firstcommunication mode includes voice and low-rate data communication mode.4. The mobile terminal of claim 1, wherein the second communication modeincludes a high-rate data communication mode.
 5. A method for acquiringat least one channel in a mobile terminal, the method comprising:attempting to acquire a channel for a first communication mode;switching the first communication mode to an idle state if the channelfor the first communication mode is acquired; attempting to acquire achannel for a second communication mode within a predefined time;switching the second communication mode to an idle state if the channelfor the second communication mode is acquired; and stopping attemptingto acquire the channel for the second communication mode if thepredefined time is elapsed.
 6. The method of claim 5, wherein at leastone of the attempting to acquire the channel for the first communicationmode and the attempting to acquire the channel for the secondcommunication mode further comprises attempting to acquire the channelfor the first communication mode and the channel for the secondcommunication mode, respectively, according to a channel list of eachcommunication mode contained in a Preferred Roaming List(PRL) filestored in a memory of the mobile terminal.
 7. The method of claim 5,wherein the first communication mode includes voice and low-rate datacommunication mode.
 8. The method of claim 5, wherein the secondcommunication mode includes a high-rate data communication mode.